1. Field of the Invention
This invention relates to a vibration apparatus for a concrete molding box which imparts vibration in a vertical direction to a concrete molding box so that a dense and homogeneous product can be obtained when a concrete product is molded.
2. Description of the Prior Art
Apparatuses for vibrating a concrete molding box according to the prior art employ the construction wherein a weight is eccentrically fixed to each rotary shaft and vibration generated by rotating the rotary shaft is transmitted to a concrete molding box.
The optimum amplitude of vibration is different depending on the weight and packing ratio of a concrete product. When a vibrating force is changed, whenever necessary, during molding of the concrete product, a homogeneous product can be obtained at a high speed. Particularly in the case of concrete molding using a quick mold release system, the vibrating force must be changed during molding.
In the conventional vibration apparatus for a concrete molding box, however, the range in which the vibrating force can be increased or decreased is narrow, and the expansion of the range has been desired.
To satisfy the requirement described above, the present invention aims at providing an apparatus for vibrating a concrete molding box which expands the range in which the vibrating force can be increased or decreased.